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Sanding profile
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September 19, 2011, 04:13:51 PM
This is how I make profile sanders. First I cut the profile out on a cnc.

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Engineering 30 plus years


September 19, 2011, 04:15:40 PM
#1
Next I apply sticky back sandpaper to the profile.

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Engineering 30 plus years


September 19, 2011, 04:17:13 PM
#2
Now it's ready for sanding the profile it was made for.

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Engineering 30 plus years


* September 19, 2011, 06:25:43 PM
#3
Thanks for the pics on your CNC application.  I never thought of machining custom sanding blocks....

Brock

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September 19, 2011, 07:28:45 PM
#4
That is a really good application, but TC is not a 3d package. Can I pick your brain on how you are doing this?

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September 20, 2011, 04:13:54 PM
#5
draw a Berier
path Mill the curve
remove all the Z axis commands in the gcode
Add Z3 if the part is 3 inches to the end of every other gcode line
then Add Z0 to the end of all the others gcode lines
Swap the z and Y axis cables
set your z axis to the top of the work and turn on the spindle
run the code
you are now milling a 3D part


I write VB programs so when I need to edit gcode and note pad isn't going to do it for me. I will write a custom program using vb. vb would change a gcode line like this "X0.042 Y0.921" to this "X0.042 Y1 Z0.921" I can also make sure the steps are not to large by adding lines of gcode.

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September 21, 2011, 04:06:16 AM
#6
oops it should read

draw a Berier
explode it twice
path Mill the curve
remove all the Z axis commands in the gcode
Add Z3 if the part is 3 inches to the gcode
then Add Z0 to the gcode
Swap the z and Y axis cables
set your z axis to the top of the work and turn on the spindle
run the code
you are now milling a 3D part


see code below

X0.0234 Y0.8941 F27.6
Z3
X0.0249 Y0.889
Z0
X0.0267 Y0.8839
Z3
X0.0288 Y0.8786
Z0
X0.0313 Y0.8733
Z3
X0.0341 Y0.868
Z0

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September 21, 2011, 07:11:00 PM
#7
If you don't want to swap the z and Y axis cables you can use windows note pad to remove all the z axis code.

X0.0174 Y0.9479
X0.042 Y0.92
X0.066 Y0.8962
X0.0895 Y0.8735

then use replace all in windows note pad to change all the Y's to Z's

X0.0174 Z0.9479
X0.042 Z0.92
X0.066 Z0.8962
X0.0895 Z0.8735

then add in the Y0 and the Y4 "Note Y4 is the length of the sanding block"

X0.0174 Z0.9479
Y0
X0.042 Z0.92
Y4
X0.066 Z0.8962
Y0
X0.0895 Z0.8735
Y4

I hope this help someone.

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Engineering 30 plus years


September 24, 2011, 08:22:58 AM
#8
Thanks. Nice work-around.

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October 03, 2011, 07:31:23 AM
#9
BTW, have you looked at any 3D CAM software?

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October 03, 2011, 04:06:58 PM
#10
I use Alphacam to program our Onsrud router but I still only program 2 1/2 D. The only thing I like about Alphacam is the auto nesting. It helps save alot of time and wood. As for as drawing I use AutoCad and save it as a DXF. Then I inport it into Alphacam. I trying to change over everthing to Turbocad and due to Price.

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October 03, 2011, 07:30:59 PM
#11
I have been looking at MeshCAM http://www.grzsoftware.com/std.php
I want to add a 4th axis onto my 4x8 CNC router, to build variable pitch feed screws. Currently, I build many of the bottle handling setups in our plant, but we have to purchase the feed screws at $3500 each. I have modeled some in TC, but I have not gotten set up to cut one. Hopefully by early next year I will have this done.

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October 04, 2011, 02:00:56 PM
#12
Is this the type of screw you wanting to build? I'm not sure what a variable pitch feed screw is. I work in wood and plastic. We make wooden screws and only use a three axis machine.

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October 04, 2011, 02:56:42 PM
#13
Here is a work around almost like the work around above but for a rotary axis.
I hope you can understand it.

Draw only one side of one thread of the screw then make the gcode using offset milling.

Now edit the gcode
Change the Y axis to a rotaty axis. Make sure you setup the rotary axis to the correct inch per turn.


use windows note pad to remove all the Z's
Then change all the Y's to Z's

X0.0174 Z0.9479
X0.042 Z0.92
X0.066 Z0.8962
X0.0895 Z0.8735

Next move all the Z's to a new line


X0.0174
Z0.9479
X10.0174
Z0.92
X0.042
Z0.8962
X10.066
Z0.8735
X0.0895


The last thing is to add the Y's

X0.0174 Y0
Z0.9479
X10.0174 Y10
Z0.92
X0.042 Y0
Z0.8962
X10.066 Y10
Z0.8735
X0.0895 Y0

(y10 for a ten inch screw)
Note: every other line "x" value has 10 added to it for ten inches.

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October 04, 2011, 07:00:48 PM
#14
Yeah, that is a similar screw. The reason for the variable pitch is where the bottles load on a rotary filling machine, they are touching one another. As the screw conveys the bottle toward the infeed star wheel, the pitch of the last thread of the screw has to be the same distance of the pockets on the starwheel. Therefore the the need for multiple pitches on the screw.

EDIT: Here is an example. I did this in v15Pro
« Last Edit: October 05, 2011, 06:03:19 AM by kmartin »

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October 05, 2011, 05:29:57 PM
#15
I see how they are made now. It look like it changes lob spacing every three turns. How long is it and what is its diameter? If I get any free time this weekend I will try to draw one and see what it will take to turn it into gcode using Turbocad cam.

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October 05, 2011, 09:19:06 PM
#16
They vary in length & pitch. Different machine types. I drew the example in the screen capture & still have the original file.

EDIT: In the image above, the screw is not for anything in particular, it was just verification that I could create the 3D model using TC. I would have to gather some data on all of our equipment to get you any specifics, along with dimensional data on all of the bottles we currently fill. We fill round, oval, rectangle, & square shaped bottles.
« Last Edit: October 06, 2011, 10:12:22 AM by kmartin »

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October 06, 2011, 11:40:47 AM
#17
Just for kicks I will still try to make a screw. Right now I know I will have the lobs increase at a known inch per turn. I will use Turbocad to make the lob and a custom program wrap the lob from end to end. I will let you know how it turns out.

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October 06, 2011, 11:48:09 AM
#18
I look foward to seeing your results. I have done no manual programming. The only CNC I have done is with TurboCAD/CAM. The way I was considreing making the feed screw was to build a 3D model & use MeshCAM to build the program to index every 1/2 degree & cutting the 3D profile.

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October 07, 2011, 04:33:14 PM
#19
This is the shape I will try to put into a screw. I'll write the screw program over the weekend.

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October 08, 2011, 12:18:12 AM
#20
I got the program wrote to convert one profile as above into a variable pitch feed screw. I'll post a few screen shots of the program later today.

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October 08, 2011, 01:53:34 PM
#21
Here are some of the program screen shots. I need to clean up the some to make it look better.

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October 08, 2011, 01:57:31 PM
#22
Put a number in the helical elements then fill in the distance advance in one revolution. Note  you can enter a diffrent distance advance for each helical element.

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October 08, 2011, 02:03:13 PM
#23
Click on the G-code you would like to turn into a screw. The screw G-code apears in the screw g-code window ready for you to copy and paste with a right click of the mouse or save it as a file. The other two code windows were for me when I wrote the program. I will remove them when I clean up the display.

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October 08, 2011, 04:53:31 PM
#24
This looks really good. Are you building this in the SDK?

EDIT: lets continue this discussion within its own thread. I created one here - http://forums.turbocad.com/index.php/topic,7316.0.html
« Last Edit: October 08, 2011, 05:03:06 PM by kmartin »

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October 08, 2011, 05:34:15 PM
#25
I wrote it in VB5 and only did to see if I could. I don't have a need to build any variable pitch screws and I'm not sure I want to get into the Turbocad SDK. I just write VB programs sometimes for kicks and then give them away to people that can use them.

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October 08, 2011, 05:36:26 PM
#26
I have some vb experience. It has been a while since I .wrote a vb program. I think 2005.

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